Hydraulic control valve for rotary servo-mechanism

ABSTRACT

A hydraulic control valve for rotary servo-actuating mechanism which is constructed with an annular casing, an input shaft provided in the annular casing and having individual oil passages respectively connected to an oil feeding source and a discharge oil vessel, and an output shaft integrally formed with a rotor, wherein the inner surface of of the annular casing and the outer surface of the rotor are shaped to define a plurality of oil chambers in conjunction with partition walls provided on the annular casing and the rotor. Oil passages are provided in the rotor communicating with the inner surface thereof toward the input shaft. A sleeve is provided between the shafts. Long grooves are provided on the outer surface of the input shaft or in the sleeve oblique relative to the center axis of the shaft, and ports are provided in the sleeve or the shaft, respectively. Relative sliding motion between the sleeve and inner shaft or relative rotational movement therebetween act to control the flow of fluid.

[451 Sept. 16, 1975 HYDRAULIC CONTROL vALvE FOR ROTARY SERVO-MECHANISM Primary Examiner-Paul E. Maslousky [75] inventors: Youichi Saida Kawasaki; Hajime Attorney, Agent, or Firm-Wenderoth, Lind & Ponack Ito, Yokohama; Kojiro Imanaga, Tokyo, all of Japan ABSTRACT [73] Assignee: Mitsubishi Kinzou Kogyo Kabushiki Kaisha, Tokyo, Japan Apr. 26, 1973 Filed: A hydraulic control valve for rotary servo-actuating mechanism which is constructed with an annular casing, an input shaft provided in the annular casing and having individual oil passages respectively connected 211 Appl. No.: 354,882

to an oil feeding source and a discharge oil vessel, and [30] A gg gt f g Pnonty Data an output shaft integrally formed with a rotor, wherein the inner surface of of the annular casing and the outer surface of the rotor are shaped to define a plurality of oil chambers in conjunction with partition walls provided on the annular casing and the rotor. Oil

Apr. 28, 1972 [52] US. 91/375 R; 91/376 R II.- CL.............................................. p g are provided in the rotor communicating [58] Fleld 0f 91/375 with the inner surface thereof toward the input shaft.

A sleeve is provided between the shafts. Long grooves [56] References are provided on the outer surface of the input shaft or UNITED TA PATENTS in the sleeve oblique relative to the center axis of the shaft, and ports are provided in the sleeve or the shaft,

9l/375 91/375 respectively. Relative sliding motion between the 91/375 sleeve and inner shaft or relative rotational movement g therebetween-act to control the flow of fluid.

2,398,586 4/1946 Maddox.......

2,466,415 4/1949 Greenland 3,103,209 9/1963 Bekkala et al.

3,125,002 3/1964 McCombs, FOREIGN PATENTS OR APPLICATIONS 2 Claims, 38 Drawing Figures 905,542 9/1962 United Kingdom................... 91/375 PATENTEBSEPYSISYS 3 905,275

' SHEET 4 FlG.4c

PATENIEU 3. 905,275

SHEET 7 FIG.7c

PATEN? ED 35F I 975 FIG.|I0

FIGQIIb PATENTED SEP I 6 I975 SHEET HYDRAULIC CONTROL VALVE FOR ROTARY SERVO-MECHANISM This invention relates to a hydraulic control valve, or, more particularly, it is concerned with a hydraulic control valve for a rotary servo-mechanism which performs not only relative rotational movement between the input shaft and the output shaft, but also relative reciprocal movement in the axial direction between the input and output shaft.

Devices for converting rotational input motion into linear output motion in response to this input motion have been known in various constructions. However, these known devices require a large number of complicated mechanisms such as screws,gears, splines, etc.,. which are liable to not only complicate the structure, and lower the mechanical efiiciency thereof, but also tend to bring about wear and tear of the device and shorten the serviceable life thereof. Furthermore, in the heretofore known devices of this sort, it has been difficult to obtain an output in response to the summation or difference of two kinds of inputs.

It is therefore a primary object of the present invention to provide a servo-control valve having a simple construction for use in a rotary servo-mechanism which is operated by a relative rotational motion, or linear sliding motion in the axial direction, or further a com-' posite motion between the outputshaft and' the input shaft, and, then produces an output from the output shaft in response to summation and difference in two kinds of displacement input.

Itis anotherobject of the present invention to providea servo-actuatior having a simple construction and easy; operation, which isprovided with a control valve capable'of generating a desired output in response to summation or difference in two different values.

'Iheuforegoing-objects and detailed construction and operation of the device according to the present invention will become more apparent from the following description thereof when read in conjunction with the accompanying drawings.

In the drawing:

FIG. 1 is a-Iongitudinal crosssection showing a hydraulic rotary servo-mechanism, in which the hydraulic control valve according to the present invention is provided;

FIG. 2a is a cross-sectional view of theservo mechanism shown in FIG. 1 above taken along the plane II- FIG. 2b is a cross-sectional view of a modified construction thereof;

FIGS.- 3a ancl 3b are schematic diagrams showing connections of the feeding and discharging system for the device shown in FIG. 2, in which FIG.3a is for clockwise rotation of the rotor, and FIG. 3b'is for coun- FIG. 9 is a longitudinal cross-section showing another embodiment of the rotary servo-mechanism according to the present invention; I

FIGS. 10a and 10b show the detailed construction of the input shaft of the device shown in FIG. 9; A

FIGS. 11a and 11b are details of the construction of the piston rod used in the device shown in FIG. 9;-

FIG. 12 is' a longitudinal cross-sectionof'a'further embodiment of the servo-mechanism according to the present invention;

FIGS. 13a and 13b show details of the'construction of the pistonrod used in the device shown in FIG. 12, and

FIGS. 14a and 14b show details of the structure of the sleeve used in the device shown in FIG. 12.

Referring now to FIGS. 1 and 2a which show' the rotary servo mechanism provided with the hydraulic control valve according to the present invention, the device has an annular casing l, and input shaft 4 and an output shaft 6, both of which pass through the center part of the annular casing 1 axially thereof. As seen from FIG. 1, the annular casing lis tightly sealed by the end walls 2 and 3 fitted at both ends of the casing. A rotor 5 is integral with the ou'tput shaft 6 within'the annular casing. More specifically, the rotor 5 is provided on its inner surface with a gun metal liner 7 which maintains smooth rotation of the rotor and output shaft 6 around the outer periphery of the input shaft 4 along with oil-tightnesstherebetween. The output shaft 6 is also mounted on the outer periphery of the input shaft 4 throughrthe liner 7.

As shown in FIG. 2a, the annular casing 1 is provided with a pair of partition walls 12 and 13 which project inwardly to the center part of the casing. Also, the rotor 5 is provided with a pair of outwardly extending wings 9 and 10 positioned at equal intervals therearound. Although not shown clearly in thedrawing, the extreme end of each of the extended wings is provided with a sealing material to enable the outwardly extending wings. 9 and-10 to oil-tightly. contact with and to be freely slidable along the inner peripheral surface of the annular casing. On the other hand, the partition walls 12 and 13 oil-tightly. contact the outer periphery of the rotorsrAlthough, in this embodiment of FIG. 2a, the rotor 5 is provided with'a pair of wings 9 and 10, and the annular casing isprovided with a pair of partition walls 12 and 13, the number of wings formed on the rotor and the partition wallformed on the inner periphcrete hydraulic actuating chambers 25, 26, 27 and 28 between theouter periphery. of the rotor 5 and the inner periphery of the annular casing 1. I

direction two passages 23a and 23b and 24a and 24b,

respectively. These passages 23a, 23b, 24a, and 24b are respectively connected to the hydraulic actuating chambers 25, 26, 27, and 28. Further, the annular pas- I sages 23 and 24, for pressurized oil are opposed to the oil ports 21 and 22, respectively, in sleeve 7. The end wall 3, on the other hand, is provided with an oil feeding passage 31 communicating with a pressurized oil feeding source S and an oil discharging passage communicating with an oil discharging vessel T. Both passages 31 and 32 are respectively connected to another pair of annular oil passages 33 and 34 surrounding the outer periphery of the input shaft 4.

Within the input shaft 4, there are bored in the axial direction thereof a pressurized oil feeding passage 16 and a pressurized oil discharging passage 17. The pressurized oil feeding passage 16 is connected to the abovementioned annular oil passage 33 by way of a passage 16R radially extending within the input shaft 4, and the pressurized oil discharging passage 17 is connected to the abovementioned annular oil passage 17 by way of a passage 17R radially extending within the input shaft 4. The pressurized oil feeding passage 16 of the input shaft 4 is provided at its one extreme end with an oil feeding port 18 extending in the radial direction, and a pressurized oil discharging passage 17 is also provided at its one extreme end with two oil discharging ports 19 and 20 extending in the radial direction. Thus, the oil feeding port 18 and the oil discharging ports 19 and 20 radially formed within the input shaft and extending to the outer periphery thereof, and the oil ports 21 and 22 provided in the sleeve 7 constitute a control valve 101 for the hydraulic rotary servo-mechanism 100.

FIG. 2b is a modification of FIG. 2a, in which each of four partition members provided in the annular casing 1 is movably mounted for movement back and forth toward the center axis of the annular casing, and three partition membersare provided on the rotor each being in the form of a wedge-shaped projection. Except for this particular construction of the partition members, the construction of the control valve 101 is exactly same as that in FIG. 2a.

f In the following, the operation of the control valve 101 will be explained with regard to the rotary servomechanism shown in FIG. 2b. At the positions of the partition members in the annular casing and on the rotor, and the position of the sleeve, the pressurized oil feeding port 18 and the pressurized oil discharging ports 19 and of the inlet shaft 4 do not register with the oil ports 21 and 22 of the sleeve 7, so that the control valve 101 is in the neutral position. As can be seen from FIG. 30, when the input shaft 4 is caused to rotate clockwise from its neutral position to bring the control valve to a position as shown in FIG. 3a, the pressurized oil feeding passage 16 of the inlet shaft 4 communicates with the oil port 21 of the sleeve 7, while the pressurized oil discharging passage 17 communicates with the oil port 22. Accordingly, pressurized oil is fed into the chambers 26, 28 and 30, and discharged from the chambers 25, 27, and 29 with the consequences that the rotor 5, and hence the output shaft 6, rotates in the clockwise. direction. Conversely,.;when the input shaft 4 is caused to rotate in the counter-clockwise direction from its neutral position in FIG. 2b, and the control valve 101 is brought to a position as shown in FIG. 3b, the pressurized oil feeding passage 16 of the input shaft communicates with the oil port 22 of the rotor 5, while the pressurized oil discharging passage 17 communicates with the oil port 21 of the rotor with' the consequence that the oil is fed into the chambers 25, 27, and 29, and discharged out of the chambers 26, 28, and 30, hence the rotor 5 (and output shaft 6) rotates in the counter-clockwise direction.

The characteristic features of the present invention are that the oil ports for feeding and discharging pressurized oil can be provided in either the input shaft 4 or the sleeve 7 constituting the control valve 101 and are formed in such a manner that each of them is a long groove which runs obliquely'with respect to the center line of the inputshaft 4 at the sliding surface between the outer surface of the input shaft 4 and the inner surface of the sleeve 7, and that the input shaft 4 is slidable in the axial direction with respect to the rotor 5.

FIGS. 4a-4e show one embodiment of the constructionof the controlvalve according to the present invention, in which the oil ports 21 and 22 formed in the gun metal liner 7 on the inner surface of the rotor are long grooves which run obliquely with respect to the center axis X-X of the input shaft 4. In these figures, the oil ports 21 and 22 are formed substantially spirally in the liner 7 which has a tubular shape, although they can be v formed in curved forms other than spiral depending on necessity.

Due to provision of these oil ports 21 and 22 in the form of long grooves in the liner 7, it is possible that the pressurized oil discharging port 19 or 20 can be made to register with or be spaced from the oil ports 21 and 22, even if the input shaft 4 is shifted in the axial direction with respect to'the rotor 5; In other words, by the" back-and-forth movement of the input shaft 4 in the axial direction thereof, it is possible to open or close the control valve 101. Consequently, the control valve 101 according to the presentinvention is responsive to various input motions such as rotational motion, linear motion, or composite motion of the two.

FIGS. 5a-5g show a modification of the control valve shown in FIGS. 4a, 4b, and 40 above, wherein a pres surized oil feeding port 18 and pressurized oil discharging ports 19 and 20 are provided in a spiral form on the outer surface of the input shaft 4, while ordinary circular ports 21 and 22 are formed in the inner surface of the liner 7. The operating principle is exactly same as that in the embodiment shown in FIGS. 40, 4b, and 4c.

FIGS. 6a-6e show still another modification of the control valve according to the present invention, wherein the liner 7 is in contact with the input shaft 4 as an input member which is freely rotatable and freely slidable in the axial direction, and a spiral oil feeding port 21 and spiral oil discharging ports 22 and 22a are formed in the liner 7.

FIGS. 7a-7e show a further modification of the control valve according to the present invention, wherein the liner 7 is used as the input member, while the shaft 4 is fixed, and in which the spiral oil feeding port 18 and the spiral oil discharging port 19 are formed.

FIG. 8 shows another embodiment of the hydraulic rotary servo-mechanism having the hydraulic control valve according to the present invention. In this embodiment, the inner surface of the annular casing has a substantially oval shape in cross-section and a plurality of partition members 9A through 9N are fitted on the rotor in a freely, outwardly and inwardly slidable manner. These partition members are urged outwardly in the radial direction by spring force exerted by springs 35A through 35N for each partition member. The construction of the control valve 101 provided in the center axis of this servo-mechanism is also exactly same as those explained in the foregoing.

Referring now to FIG. 9 which shows another embodiment of the rotary servo-mechanism according to the present invention, a hydraulic servo-actuator 50 of the present invention consists of a hydraulic cylinder 1, a cylindrical casing 4 integrally and concentrically formed with the hydraulic cylinder 1, apiston 2 which is accommodated within the hydraulic cylinder 1 and is freely slidable along the inner periphery of the hydraulic cylinder 1, and a piston rod 6 which is integrally formed with the piston 2 and projects outward through an end wall 1A covering one end of the cylinder 1.

The cylindrical casing 4 is also closed at its one end opposite the end wall 1A with another end wall 5. The abovementioned piston rod 6 also extends toward the cylindrical casing 4 (i.e., toward the left side of the drawing) and is in oil-tight relationship with the inner wall of the cylindrical casing 4. The piston rod 6 is also provided with a concentric bore 7 therewithin which opens at the left end inside the cylindrical casing 4. Into this concentric bore 7, there is inserted one end of a rod member, or an input shaft 3, which is introduced into the cylinder interior through an opening 20 formed in the end wall 5 of the cylindrical casing 4. The input shaft 3 passes through the opening 20 of the end wall of the cylindrical casing 4 in a freely slidable and rotatable manner. Within this end wall 5 of the cylindrical casing 4, there are formed a pressurized oil feeding port 10 connected to an appropriate pressurized oil feeding source (not shown) such as a hydraulic pump, etc., and a pressurized oil discharging port 1 1 connected to a discharge oil vessel (not shown). The pressurized oil feeding port, or oil intake, 10 is further connected to an annular groove 12 formed on the inner surface of the opening 20 of the end wall 5 through an oil passage 10A which is also formed within the end wall 5. Likewise, the pressurized oil discharge port 11 is connected to another annular groove 13 formed on the inner surface of the opening 20 of the end wall 5 through another oil passage 11A.

As shown in FIGS. 9, 10a, and 10b, the input shaft 3 is provided therewithin with a pressurized oil feeding passage 14 and a pressurized oil discharging 15 which are parallel to each other in the axial direction of the input shaft 3. Both pressurized oil feeding passage 14 and pressurized oil discharging passage 15 are respectively connected to the annular groove 12 for oil feeding and the annular groove 13 for oil discharging by way of radially extending passages 14A and 15A. Further, these pressurized oil feeding passage 14 and pressurized oil discharging passage 15 are connected at their other ends (i.e., right side of the sheet of the drawing) with long grooves 16, and 17 and 17a, respectively formed on the outer periphery of the input shaft 3. According to FIG. 10a, these long grooves 16, 17, and 17a are formed on the outer periphery of the input shaft in a spiral direction and substantially parallel to each other. However, the shape of the long grooves is not limited to the spiral form alone, but any other appropriate shape may be chosen depending on the required responsive characteristics of the output shaft 6.

As shown in FIGS. 9, 11a, and 11b, the piston rod (output shaft) 6 is provided within its cylindrical wall with mutually parallel oil passages 18 and 19 extending in the axial direction thereof. The oil passage 18 is open at one end thereof to the bore 7 and at the other end to the chamber A on the left side of the piston 2. Also, the oil passage 19 is open at its one end to the bore 7 and at the other end to the chamber B on the right side of the piston 2.

The opening 18A of the oil passage 18 and the opening 19A of the oil passage 19 opening into the bore 7 are positioned in such a manner that each of them is circumferentially aligned with the center part of each of the abovementioned long grooves 16, 17, and 17a formed on the outer peripheral surface of the input shaft 3. Thus, the long grooves 16, 17, and 17a are connected to the pressurized oil feeding passage 14 and the pressurized oil discharging passage 15, and the oil passages 18 and 19 formed in the cylindrical wall of the piston rod 6, both of which are open to the inner surface of the bore 7, constitute the hydraulic control valve 51 for the servo-actuating mechanism according to the present invention.

Both input shaft 3 and piston rod 6 not only rotate mutually along the control valve 51, but also mutually slide in the axial direction.

In the actual operation of the servo-actuating mechanism according to the present invention having the above-described construction, when the control valve is initially set at the neutral position as shown in FIG. 10b, both the long'groove 16 for oil feeding of the input shaft 3 and long grooves 17 and 17a for oil discharging are circumferentially offset from and thus completely disconnected from the two oil passages 18 and 19 formed in the cylindrical wall of the piston rod 6, and there is no flow of the pressurized oil in and out of the two oil chambers within the cylinder, and hence no movement of the output shaft 6.

When the input shaft 3 is moved rightward, the oil passages 18A and 19A formed in the cylindrical wall of the piston rod 6 are register with the long grooves 17 and 16, respectively, because the long grooves 16, 17, and 17a formed in the input shaft 3 are oblique with respect to the center axis of the shaft. In this state, pressurized oil is fed into the right oil chamber B of the cylinder 1 through the pressurized oil feeding port 10, oil passage 10A, annular groove 12, oil passage 14, long groove 16, and oil passage 19. Simultaneously, the

pressurized oil within the left oil chamber A is discharged into the discharge oil vessel through the oil passage 18, long groove 17, oil passage 15, annular groove 13, oil passage 11A, and pressurized oil discharging port 11. Conversely, when the input shaft 3 is moved leftward, the oil passages 18A and 19A are brought into register with the long grooves 16 and 17, respectively. In this state, pressurized oil is fed into the left oil chamber A of the cylinder 1 through the pressurized oil feeding port 10, oil passage 10A, annular groove 12, oil passage 14, long groove 16, and oil passage 18, and, at the same time, pressurized oil in the right oil chamber B is discharged into the discharge oil vessel through the oil passages 19, 19A, long groove 17a, oil passage 15, annular groove 13, oil passage 11A, and pressurized oil discharging port 11. Consequently, the output shaft of the piston moves rightward.

Further, when the input shaft 3 is rotated in the counter-clockwise direction from its neutral position as shown in FIG. b, the long groove 16 of the input shaft 3 register with the oil passage 18 of the piston rod 16 with the consequent registering of the long groove 170 with the oil passage 19. Accordingly, the pressurized oil is introduced into the left oil chamber A of the piston 2 through the pressurized oil feeding port 10, oil passage 10A, annular groove 12, pressurized oil feeding passage 14, long groove 16, and oil passage 18 of the output shaft. Simultaneously, the pressurized oil in the right oil chamber B of the piston 2 is led to the presssurized oil discharging port 11 through the oil passage 19 of the piston rod 6, long groove 17a of the input shaft, pressurized oil discharging passage 15, annular groove 13, and oil passage 1 1A, and it is finally discharged into the discharge oil vessel (not shown). Accordingly, the piston 2 and the output shaft 6 perform linear movement to the right in FIG. 9. Thus, by the operation of the servo-actuating mechanism according to the present invention, the rotational movement of the input shaft 3 is converted into linear movement of the output shaft 6.

Conversely, when the input shaft 3 is rotated in the clockwise direction from its neutral position as shown in FIG. 10b, the long groove 16 of the input shaft registers with the oil passage 19 of the piston rod (output sshaft) 6 with the consequent registering of the long groove 17 with the oil passage 18. Accordingly, the pressurized oil is introduced into the right oil chamber B of the piston 2 through the pressurized oil feeding port 10, oil passage 10A, annular groove 12, pressurized oil feeding passage 14, long groove 16, and oil passage 19. Simultaneously, the pressurized oil in the left oil chamber A is discharged from the device through the oil passage 18, long groove 17, pressurized oil discharging passage 15, annular groove 13, and oil passage 1 1A. In this consequence, the output shaft 6 of the piston 2 linearly moves leftward.

FIGS. 12, 13a, 13b, 14a and 14b show other embodiments of the present invention, in which the piston rod (output shaft) 6 passes through both ends of the hydraulic cylinder 1 and extends through the entire de vice, and the input shaft 30 is in the form of a sleeve, which is rotatably and oil-tightly mounted on the outer periphery of the piston rod 6. In the embodiment shown in FIGS. 13a and 13b, the left end of the oil passages 18 and 19 formed mutually in parallel and in the axial direction of the piston rod 6 are connected to long grooves 41 and 42, respectively. The sleeve 30 is provided at its right end with a flange 31, which in turn is accommodated in an annular groove or cavity 32 formed in the left end of the cylinder 1, whereby the sleeve 30 is rotatably held in the cylinder 1.

Within the cylindrical wall of the sleeve 30, there are provided a pressurized oil feeding passage 33 and a pressurized oil discharging passage 34 extending in the axial direction thereof. The pressurized oil feeding passage 33 is connected at its right end to the pressurized oil feeding port 10 through the oil passage 10A formed within one end wall of the cylinder 1 and the annular groove 35 formed on the outer periphery of the sleeve I 30, and is open at its left end to the inner surface of the sleeve 30 (33A). In like manner, the pressurized oil discharging passage 34 is connected at its right end to the pressurized oil discharging port 11 through the annular groove 36 of the sleeve 30 and the oil passage 11A in the cylinder 1, and is' open-at its left end to the inner surface of the sleeve by means of two openings 34A and 34B. Thus, these openings 33A, 34A and 34B formed within the cylindrical wall of the sleeve 30 and respectively connected to the pressurized oil feeding passage and the pressurized oil discharging passage, and the long grooves 41 and 42 formed on the outer periphery of the piston rod 6 and connected respectively to the oil passages 18 and 19 formed within the piston rod 6 constitute the hydraulic control valve 51 for this embodiment. The operation and performance of the control valve and the piston 2 are exactly same as those of the previously explained embodiments.

Further, in the case of the embodiment shown in FIG. 12, the input sleeve 30 is confined so that it will not move in the axial direction thereof. However, it is of course possible that this member can be fitted in the cylinder so as to be freely slidable in its axial direction. By so doing, not only the rotational movement of the input member, but also the linear movement thereof in the axial direction can be imparted to the control valve 51, whereby an output responsive to such input can be generated at the output shaft (i.e., piston rod) 6. Still further, the left ends of the pressurized oil feeding passage 33 and the pressurized oil discharging passage34 formed within the cylindrical wall of the sleeve 30 are placed in communication with the long groove 21 for oil feeding, and the long grooves 22 and 22a, respectively, as shown in FIG. 6b, which is then connected to the oil passages 18 and 19 provided within the piston rod 6. There is no difference in the operating principle of this embodiment from that of the other embodiments. 7

As stated in the foregoing, the present invention makes it possible to perform desired various motions of the output means by appropriately selecting the shape of the long groove to be provided in the input shaft or output shaft which constitute a component part of the control valve according to the present invention. For example, by providing long grooves of twisted form other than the spiral form, a desired non-linear motion can be obtained at the output. Also, it is possible to convert rotational movement into linear movement by simple operation of the control valve; in which no additional device other than this control valve is required. Furthermore, by use of the control valve according to the present invention, an output responsive to a summation or difference of two input forces can be easily obtained, hence the industrial merit of this particular control valve is considered to be great.

What we claim is:

l. A hydraulic servo-actuating mechanism comprising an annular casing having an internal bore with a central axis; a plurality of first partition walls projecting from the inner surface of said bore radially inwardly toward said central axis of the casing; end walls closing the axial ends of said bore; an input shaft extending axially through said bore and rotatably positioned therein for rotation around said central axis, said input shaft having therein hydraulic fluid passages connected to a hydraulic pressure source and to a hydraulic fluid reservoir; an output shaft means rotatably mounted on the outer periphery of said input shaft and having a rotor thereon with a plurality of second partition walls which are wedge-shaped projections integral with said output shaft radially outwardly projecting therefrom with the ends thereof slidingly engaging said inner surface of said casing, said first partition walls being movably mounted in said casing for radial back and forth movement and resiliently urged radially inwardly against the outer perhipheral surface of said output shaft, whereby hydraulic actuating chambers are formed in the casing between adjacent pairs of said first and second partition walls, said output shaft means having therein hydraulic fluid passages selectively communicating said fluid passages in said input shaft with said hydraulic actuating chambers; and control valve means interposed between said input and output shafts to control communication between said fluid passages in said input shaft and said hydraulic actuating chambers in said casing through said fluid passages in said output shaft, said control valve means comprising mounting means for slidably mounting said input shaft for sliding movement along said central axis relative to said output shaft means, a liner sleeve interposed between said input and output shafts and secured to said output shaft so as to be rotatable therewith, a first set of fluid flow control openings in the outer surface of said input shaft communicating with said fluid passages in said input shaft, and a second set of fluid flow control openings in the inner surface of said liner sleeve communicating with said fluid passages in said output shaft means, one of said first and second sets of openings being ports and the other being grooves extending obliquely relative to said central axis.

2. The mechanism according to claim 1, wherein said second set of control openings are grooves extending obliquely relative to said central axis and extend through the radial thickness of said liner sleeve.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,905,275 Dated September 16, 1975 Inventor s YOUICHI SAIDA; HAJIME ITO; and KOJIRO IMANAGA It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the Heading (73) Assignee: for"Mitsubishi Kinzoki Kogyo Kabushik' Kaisha" read -Mitsubishi Kinzoku Kabushiki Kaisha;

Signed and Sealed this twenty-fourth Day Of February 1976 [SEAL] A ttest:

RUTH- C. M A'SON C. MARSHALL DANN Allcstlng Officer Commissioner ofPaienrs and Trademarks 

1. A hydraulic servo-actuating mechanism comprising an annular casing having an internal bore with a central axis; a plurality of first partition walls projecting from the inner surface of said bore radially inwardly toward said central axis of the casing; end walls closing the axial ends of said bore; an input shaft extending axially through said bore and rotatably positioned therein for rotation around said central axis, said input shaft having therein hydraulic fluid passages connected to a hydraulic pressure source and to a hydraulic fluid reservoir; an output shaft means rotatably mounted on the outer periphery of said input shaft and having a rotor thereon with a plurality of second partition walls which are wedge-shaped projections integral with said output shaft radially outwardly projecting therefrom with the ends thereof slidingly engaging said inner surface of said casing, said first partition walls being movably mounted in said casing for radial back and forth movement and resiliently urged radially inwardly against the outer perhipheral surface of said output shaft, whereby hydraulic actuating chambers are formed in the casing between adjacent pairs of said first and second partition walls, said output shaft means having therein hydraulic fluid passages selectively communicating said fluid passages in said input shaft with said hydraulic actuating chambers; and control valve means interposed between said input and output shafts to control communication between said fluid passages in said input shaft and said hydraulic actuating chambers in said casing through said fluid passages in said output shaft, said control valve means comprising mounting means for slidably mounting said input shaft for sliding movement along said central axis relative to said output shaft means, a liner sleeve interposed between said input and output shafts and secured to said output shaft so as to be rotatable therewith, a first set of fluid flow control openings in the outer surface of said input shaft communicating with said fluid passages in said input shaft, and a second set of fluid flow control openings in the inner surface of said liner sleeve communicating with said fluid passages in said output shaft means, one of said first and second sets of openings being ports and the other being grooves extending obliquely relative to said central axis.
 2. The mechanism according to claim 1, wherein said second set of control openings are grooves extending obliquely relative to said central axis and extend through the radial thickness of said liner sleeve. 